Patent GB-191214945-A (GB)
Title: Improvements in Call-distributing Telephone Systems.
Inventor: CLAUSEN HENRY PETER
IPC: H04M3/523
Filed: 1912-06-26
Granted: 1913-06-26
Abstract: 14,945. Clausen, H. P. April 26, 1911, [Convention date]. Exchange systems; semi - automatic exchange systems. - Subscribers' lines which originate a large number of calls are connected at the exchange to switches of preliminary selector type which distribute the calls among the idle operators. The other lines are connected to multiple jacks at the exchange in the usual way, and the trunks from an operator's position to the selecting switches may be made busy when. there is any ordinary or distributed call waiting in the operator's group. Fig. 1 shows two subscribers 1, 2 connected to the exchange jacks, Fig. 2, through calldistributing switches and a subscriber 3 connected directly to the exchange jacks. Fig. 3 shows an operator's cord circuit. When subscriber 1 removes his receiver a circuit is completed from the battery lead 17 through the winding 15 of line relay 16, contacts 13, 12 of cut-off relay 14, lines 7, 8, contacts 18, 19 and winding 20 of cut - in relay 21 to ground. The actuation of relays 16, 21 completes the actuating circuit of the distributing switch over the interrupter 27, the actuating - magnet 28, contacts 25, 24, contacts 30, 31, 23, 22, segment 34 of the switch, brush 35, contact 36. &c., and lead 78. In the case of a line of a busy position the lead 78 is grounded, but when an idle line is reached the current passes over a high-resistance path from the contact 31 through the contacts 43, 44 of line relay 16, winding 45, and winding 47 of cutoff relay 14 to earth. The actuation of cut-off relay 14 breaks the circuit of the motor magnet, but a locking circuit for the relays is completed from the lead 17 over the coils 48, 49, 45, and 47. The contacts of the relay 14 now connect the subscribers' lines through segments of the distributing switch to the leads 62, 69. The lead 62 being earthed, the trunk-relay 72 between the battery lead and the line 69 is now actuated, and the contacts 74, 75 connect to ground the line 78 of this switch, and also, through the lead 80, the similar lines 78 of all other trunk lines leading from distributor switches to this position. The contacts 86, 87 bring into circuit the line-lamp 90, and when the answering - plug 92 of the operator's cord circuit is inserted in the jack, the trunk cut-off relay 65 is energized over a circuit through the sleeve 97 and the supervisory relay 94. The armature 99 breaks the contact 76, 77, thus retaining the earth on the line 78 of this trunk, but removing the earth on the line 80 leading to other trunks at this position. The circuit of the answering supervisory signal 123, however, is made over the relay 152, which places earth on the line 80 over its contact 154. When the plug is inserted in the jack, the cord circuit is connected through the distributing switch to the leads of the calling subscriber. After enquiry, the calling plug 129 is inserted in the jack of the wanted subscriber in the usual way, whether he is connected to a distributing switch or not. The ringing key 128, 144 brings the generator 138 into circuit. When a subscriber, as 3, makes a call the circuit of line lamp 158 includes the relay 115, the contact 117 of which makes the position busy to distributing switches by connecting earth on the line 80. Each operator's position is preferably divided into two distinct groups so that a call can be received on one group while a previous call is being dealt with on the other group. If the cord circuits of a position are occupied with manual calls, the position may be made busy by depressing the call-bearing key 114. In very busy times, a number of distributed calls may be received at one position by depressing the keys 83, thus removing the ground from a trunk line unless that line is itself busy. Metering systems.-The number of distributed calls dealt with at any position is recorded on a meter 108, the relay 104 of which is actuated by a circuit over the contacts 101, 102 of the trunk relay 72. To prevent more than one call from being registered should a subscriber break his line circuit a number of times, the relay 104 is provided with a hold-on coil 109, the circuit of which is made over the normally closed contacts of the trunk cut-off relay 65.